IDA3C Weber Troubleshooting Options

[Cfletch]

Hey there everyone, working on getting my 6 conversion going here and I was able to hook up a temp fuel system in place of my tank while I am waiting on a few parts. I wanted to get the car to idle with its new fuel pump (not yet regulated down to 3.5psi) rated at 5 PSI max. I wanted to get the carb bodies full of fuel and get some pressure into the system and as soon as the pump turned on with the ignition the carbs essentially started dumping fuel down my intakes. Almost as if there was an internal leak causing fuel to just enter their respective cylinders. I'm new to down draft webers so this confuses me. I popped the top off of one of the carbs and noticed the fuel level was extremely low in the bowls so it was not like the needle and seat were stuck or a float was stuck causing it to overfill. Kind of stumped here as these carbs are rebuilt. Really any suggestions are good here. the float level was set, the needle and seats are good and not sticking at all.

I read somewhere but not in much detail that the bowls are vented? I have these little plunger-esq things in each vent tube that I have not yet pulled out. Would that be the source of my problem? If the bowls couldn't vent its just pressurizing the changes and causing the fuel to just leak down into the engine?

[Cfletch]

Hey friends, bit of an update for you all:

I've been sick/busy with work so slow progress on the car from the past weeks. I was able to get the regulator plumbed and set it for 3.5PSI to carbs and also mounted the gas tank. I tried to start it the other day and it just refused to start so I broke out the either and it fired off right away then ran and barely held an idle so I was lost as to what had happened. If seemed like the passenger side bank just did not want to run well at all and I babied the throttle to keep it alive. I also noticed the car just refused to go back down to a proper idle even when I was not babying it.

Come back to this weekend, I decided I needed to just pull that carb. Main reason was I wanted to blast some compressed air through everything once again because my idle mixture screw on cylinder 1 didn't seem to impact the engine at all so I figured it must have been clogged. Additionally I noticed that the same carb just had 0 accel pump. Meaning it just wouldn't squirt a single drop out of any of the pumps furthering my idea that I just needed to take off the carb and see what's going on.

I pulled it and blasted everything with air and confirmed airflow through every hole I could easily check. The accel pump was clogged in the center hole of the 3 in a horizontal line on the block that sends air signal to each of the 3 throats. Not sure proper name of that block I am referring to, but if you rebuilt them you'll know what I'm talking about. I used some compressed air in each of the brass little holes at the perimeter of the block and something shot me in the face from the middle hole when blasting which made me certain that was my problem.

I also noticed that one of my new needles was sticking and that was evident because the float was extremely low with fuel. I replaced with an older one that I took off when I rebuilt them and then reassembled that bank with the new carb after doing some baseline settings once again.

Turned on ignition and let the pump fill up the bowls and then gave it a few pumps and watched the pump nozzles to see if they squirted any fuel down (they did) and it started pretty much right away. My idle issue was resolved and it ran infinitely better than the prior attempt from the other week.

With all of that being said, I need to go back and now tune it a little better. My current issues is that 1 bank is running cooler (richer??) than the other because its backfiring out of the exhaust more than it should even when holding a rev at around say 3k. Need to start researching more to see what might be going on there. I have my synrometer and that seems to be reading a lower value than it should at around 2. From my quick searches people are usually up around the 5 mark? I'm not sure how to increase that without changing the idle speed drastically so I need to spend a good portion of my night looking at videos to see what might be going on there.

Tomorrow I have the day off so will go back to it to keep working on everything. One goal is to get my tach to work with a unit I got online that amplifies and changes the signal to work with my MSD box and my 4 cylinder tach. I'd like to get that up so I know where I am at on the gauge.